Microdiscectomy vs Laminectomy
The spinal cord runs from the lower part of the brain and ends around the lower border of the L1/L2 vertebrae. The spinal cord runs as a bunch of spinal nerves below L1/L2 known as cauda equina. The spinal cord/dural sac is contained inside the central canal formed by the vertebrae. The individual vertebrae are separated from each other by the intervertebral disc.
The intervertebral disc has watery consistency in its center with a firm outer ring. The intervertebral disc serves to cushion the impact between the adjoining vertebrae. At each segment, spinal nerves exit the vertebral column through the intervertebral foramen. The intervertebral foramen is surrounded by the intervertebral disc, lamina, and facet joints.
Disc herniation known as the prolapsed intervertebral disc (PIVD) may compress the dural sac/ spinal nerves. The prolapse of the disc material may also narrow the intervertebral foramen. The intervertebral disc undergoes changes with advancing age in the form of decreased water content and minor cracks in the outer ring. With repetitive motion or due to sudden trauma the inner soft material may herniate through the outer ring.
The compression of the dural sac or the spinal nerve roots leads to symptoms of radiating pain also known as Conservative management. The sciatica symptoms may include a tingling sensation in the lower extremities. In severe cases of compression, there may be symptoms of numbness and weakness in the legs.
Patients with neural canal narrowing known as lumbar canal stenosis often experience pain in the legs upon walking and bending backward. The pain in the legs in walking does not get better with rest and instead subsides only on bending forward. Similarly, patients may complain of pain on descending a flight of stairs but with no symptoms on ascending.
The unique symptoms of lumbar canal stenosis are due to the anatomical makeup of the lumbar spine. The space inside the neural foramen narrows on bending backward. With a herniated disc, the precarious space is further narrowed on extending the spine leading to symptoms of claudication.
The initial management of sciatica is conservative. Conservative management is done in the form of modification of activity, pain relief medications such as ibuprofen, and heat/cold therapy. Once the initial inflammatory phase resolves, physical therapy may be initiated to help in strengthening the back muscles.
In patients with continued symptoms, nerve root injections or caudal epidural injections may be tried. Surgical treatment in the form of microdiscectomy or laminectomy is done when all forms of conservative management have been tried and failed.
During microdiscectomy surgery, the spine surgeon gives a small incision in the lower back while the patient is under general anesthesia. The surgery may also be done in an outpatient setting with local anesthesia depending upon the patient’s underlying condition.
The surgeon uses magnifying glasses and an endoscope to visualize the surgical field through a small incision. The muscles are carefully separated and the lamina is identified. A small fragment of the lamina is removed to visualize the intervertebral disc.
The surgeon then uses an instrument to carefully take small bites of the disc material until the disc herniation is removed. During the process, the nerve roots are protected using careful retraction. The surgeon closes the incision in layers and a small tape is applied at the incision site.
The laminectomy surgery may be a part of the microdiscectomy surgery while removal of the herniated disc or be done to increase the space of the canal. During surgery, the surgeon gives an incision at the back at a level determined preoperatively. The muscles and tissues are carefully separated.
A part ligamentum flavum is removed. The lamina is then removed to increase the space available for the neural tissues. The lamina may be partially removed known as a laminotomy or completely removed on one side known as a laminectomy. The lamina may also be opened up to create a hinge (laminoplasty) to allow more space for the neural structures.
The surgeon may perform laminectomy only on one side or may perform on both sides. During the surgery, if the surgeon determines any instability of the spinal segment, fusion surgery may be performed.
Similar to microdiscectomy, the majority of the patients undergoing laminectomy are able to go home the same day of the procedure. With minimally invasive techniques such as endoscopic laminectomy, the recovery is short and the patients are able to return to their activities sooner.
Both the microdiscectomy and the laminectomy surgery are aimed to relieve the symptoms of sciatica. The type of surgery required is dependent upon the patient’s underlying cause of lumbar radiculopathy. Both the surgeries are highly successful in treating sciatica. Your spine surgeon will discuss the type of surgery and the outcomes before the procedure.